1. Technical Field
The disclosure relates generally to color changing compositions, and more particularly to highlighting marking compositions that change from a first color to a second color upon application of an eradicator.
2. Brief Description of Related Technology
Eradicable mixture systems, such as inks, generally include two components. The first component is typically an aqueous mixture that includes a dye that can be rendered substantially colorless when contacted with a substance such as a reducing agent, an oxidizing agent, acidic compounds, or basic compounds (such as hydroxides and amines). The second component is typically an aqueous eradicator fluid which includes one of the aforementioned substances. Thus, a consumer can write with the eradicable mixture and, if correction is necessary, apply an eradicator fluid to the written markings in order to decolorize (or erase) the markings.
Textual information is often highlighted by applying a fluorescent ink there over (e.g., a highlighting ink is applied over a written marking previously made on a substrate such as paper). A typical fluorescent highlighting ink has a translucent quality, which allows a consumer to apply the highlighting ink over the textual information while still being able to read and/or otherwise comprehend the information under the fluorescent ink marking. Although highlighting allows the consumer to selectively emphasize specific information, other areas of the substrate that do not include any information are also highlighted. Such highlighted areas can cause photocopies of the highlighted text to be unreadable.
Multiple colorants are often mixed together to provide the overall color of a particular highlighting composition. Combinations of multiple colorants can cause the highlighting composition to become somewhat dark or muddy in appearance, particularly when a highlighting composition is attempted in a primary color. This darkening of the composition can cause the (attempted) primary color to substantially appear as a secondary color to the human eye. For example, highlighting compositions which are intended to be blue or red can appear grayish or even somewhat black.